A 33-year-old man with gait instability, weakness of the left lower extremity, decreased visual acuity in the left eye, and urgency and urine incontinence was diagnosed of relapsing-remitting multiple sclerosis. He was treated with natalizumab (300 mg intravenously every 4 weeks) as first-line therapy, which reached at 6 months a favorable clinical evolution and dramatic radiological improvement (T₂-weighted lesion load decreased by 50% and no gadolinium-enhancing T₁ lesions) sustained over the course of 8 years. This clinical case shows the efficacy of natalizumab in a real-world setting and, particularly, the sustained effect of this drug in the long term as demonstrated by persistent radiological improvement. Natalizumab can be considered as the treatment of choice in relapsing-remitting multiple sclerosis forms presenting with two relapses and gadolinium-enhancing (Gd+) lesions.